Rimonabant for overweight or obesity

Novel Peripherally Selective Cannabinoid Receptor 1 Neutral Antagonist Improves Metabolic Dysfunction-Associated Steatotic Liver Disease in Mice

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing globally. MASLD is characterized by clinically significant liver steatosis, and a subset of patients progress to more severe metabolic-disorder-associated steatohepatitis (MASH) with liver inflammation and fibrosis. Cannabinoid receptor 1 (CB1) antagonism is a proven therapeutic strategy for the treatment of the phenotypes that underlie MASLD, though work on early centrally penetrant compounds largely ceased following adverse psychiatric indications in humans. We present here preclinical testing of a CB1 neutral antagonist, N-[1-[8-(2-Chlorophenyl)-9-(4-chlorophenyl)-9H-purin-6-yl]-4-phenylpiperidin-4l]methanesulfonamide (RTI-348), with minimal brain exposure when administered to mice. In a diet-induced model of MASLD-induced MASH, administration of RTI-348 decreased the total body and liver weight gain. Animals treated with RTI-348 showed reduced steatosis. Furthermore, they produced lower plasma alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH), biomarkers associated with liver damage. Mice maintained on the MASH diet had elevated expression of genes associated with profibrogenesis, immune response, and extracellular matrix remodeling, and treatment with RTI-348 mitigated these diet-induced changes in gene expression. Using an intracranial electrical self-stimulation model, we also demonstrated that RTI-348 does not produce an anhedonia response, as seen with the first-generation CB1 inverse agonist rimonabant. Altogether, the results herein point to RTI-348 as a promising neutral antagonist for MASH.

Changes in plasma endocannabinoids concentrations correlate with 18F-FDG PET/MR uptake in brown adipocytes in humans

Introduction: Recent data suggest a possible role of endocannabinoids in the regulation of brown adipose tissue (BAT) activity. Those findings indicate potential treatment options for obesity. The aim of this study was to evaluate the relationship between plasma endocannabinoids concentrations and the presence of BAT in humans. Methods: The study group consisted of 25 subjects divided into two groups: BAT positive BAT(+), (n = 17, median age = 25 years) and BAT negative BAT(-), (n = 8, median age = 28 years). BAT was estimated using 18F-FDG PET/MR after 2 h of cold exposure. The level of plasma endocannabinoids was assessed at baseline, 60 min and 120 min of cold exposure. Results: In both groups, BAT(+) and BAT(-), during the cooling, we observed a decrease of the same endocannabinoids: arachidonoylethanolamide (AEA), eicosapentaenoyl ethanolamide (EPEA) and oleoyl ethanolamide (OEA) with a much more profound decline in BAT(+) subjects. Statistically significant fall of PEA (palmitoylethanolamide) and SEA (stearoylethanolamide) concentrations after 60 min (FC = 0.7, p = 0.007 and FC = 0.8, p = 0.03, respectively) and 120 min (FC = 0.81, p = 0.004, and FC = 0.9, p = 0.01, respectively) of cooling was observed only in individuals with BAT. Conclusion: We noticed the profound decline of endocannabinoids concentrations in subjects with increased 18F-FDG PET/MR uptake in BAT. Identification of a new molecules related to BAT activity may create a new target for obesity treatment.

Off-label and investigational drugs in the treatment of alcohol use disorder: A critical review

Compounds known to be successful in the treatment of alcohol use disorder include the aversive agent, Disulfiram, the glutamatergic NMDA receptor antagonist, Acamprosate, and the opioid receptor antagonists, Naltrexone and Nalmefene. Although all four are effective in maintaining abstinence or reduction of alcohol consumption, only a small percentage of patients receive pharmacological treatment. In addition, many other medications have been investigated for their therapeutic potential in the treatment of alcohol use disorder. In this review we summarize and compare Baclofen, Gabapentin, Topiramate, Ondansetron, Varenicline, Aripiprazole, Quetiapine, Clozapine, Antidepressants, Lithium, Neuropeptide Y, Neuropeptide S, Corticotropin-releasing factor antagonists, Oxytocin, PF-05190457, Memantine, Ifenprodil, Samidorphan, Ondelopran, ABT-436, SSR149415, Mifepristone, Ibudilast, Citicoline, Rimonabant, Surinabant, AM4113 and Gamma-hydroxybutyrate While some have shown promising results in the treatment of alcohol use disorder, others have disappointed and should be excluded from further investigation. Here we discuss the most promising results and highlight medications that deserve further preclinical or clinical study. Effective, patient-tailored treatment will require greater understanding provided by many more preclinical and clinical studies.

Effects of Cannabidiol on Appetite and Body Weight: A Systematic Review

BACKGROUND AND OBJECTIVE

Cannabidiol, one of the main components of the Cannabis sativa plant, is a non-psychotropic cannabinoid that has recently drawn the attention of researchers and clinicians for its potential therapeutic applications. In this systematic review, we aim to describe the possible effects of cannabidiol in appetite and body weight.

METHODS

Both authors independently ran a thorough search in both PubMed and Cochrane databases up to 31 July, 2022 and included every peer-reviewed, original randomized controlled clinical trial that reported data on either of the said outcomes. Risk of assessment bias was performed with Cochrane's risk of bias tool and results were summarized in tables.

RESULTS

A total of 11 trials were included in this review. Of these, the majority reported on cannabidiol reducing appetite and/or body weight whilst some have found no significant changes and one trial described an increase in appetite.

CONCLUSIONS

This systematic review suggests that cannabidiol has an anorexigenic effect, correlated with a decrease in body weight. However, most of the studies included in the present review raised some concerns in terms of risk of bias. We believe further research is needed in order to clarify potential mechanisms involved in the effect of cannabidiol on feeding/appetite.

Psychosocial Consequences of Bariatric Surgery: Two Sides of a Coin: a Scoping Review

This scoping review summarizes current evidence with regard to the impact of bariatric surgery on psychological health in adults with obesity. While a large body of evidence reports major metabolic benefit and improved quality of life, there is also ample evidence suggesting an increased incidence of self-harming behavior, a greater likelihood of developing an alcohol problem and higher rates of completed suicide among bariatric patients. Being able to identify the "at risk" patient population requires more longitudinal research into the risk factors for psychological complications after bariatric surgery. Bariatric surgery remains an extremely valuable long-term treatment option for managing obesity; however, there is a need to invest in mitigating psychological complications after the surgery, such as depression, alcohol consumption, and other self-harming behaviors.

Palmitoleoylethanolamide Is an Efficient Anti-Obesity Endogenous Compound: Comparison with Oleylethanolamide in Diet-Induced Obesity

Obesity is currently a major epidemic in the developed world. However, we lack a wide range of effective pharmacological treatments and therapies against obesity, and those approved are not devoid of adverse effects. Dietary components such as palmitoleic acid have been proposed to improve metabolic disbalance in obesity, although the mechanisms involved are not well understood. Both palmitoleic acid (POA) and oleic acid (OA) can be transformed in N-acylethanolamines (NAEs), mediating the effects of dietary POA and OA. To test this hypothesis, here, we study the effects on food intake and body weight gain of palmitoleylethanolamide (POEA) and the OA-derived NAE analogue, oleoylethanolamide (OEA), in Sprague-Dawley rats with a hypercaloric cafeteria diet (HFD). Plasma biochemical metabolites, inflammatory mediators, and lipogenesis-associated liver protein expression were also measured. The results indicate that POEA is able to improve health status in diet-induced obesity, decreasing weight, liver steatosis, inflammation, and dyslipemia. The action of POEA was found to be almost identical to that of OEA, which is an activator of the nuclear peroxisome proliferator receptor alpha (PPARα), and it is structurally related to POEA. These results suggest that the dietary administration of either POA or POEA might be considered as nutritional intervention as complementary treatment for complicated obesity in humans.

Role of the Endocannabinoid System in the Adipose Tissue with Focus on Energy Metabolism

The endocannabinoid system is involved in a wide range of processes including the control of energy acquisition and expenditure. Endocannabinoids and their receptors are present in the central nervous system but also in peripheral tissues, notably the adipose tissues. The endocannabinoid system interacts with two main hormones regulating appetite, namely leptin and ghrelin. The inhibitory effect of the cannabinoid receptor 1 (CB₁) antagonist rimonabant on fat mass suggested that the endocannabinoid system can also have a peripheral action in addition to its effect on appetite reduction. Thus, several investigations have focused on the peripheral role of the endocannabinoid system in the regulation of metabolism. The white adipose tissue stores energy as triglycerides while the brown adipose tissue helps to dissipate energy as heat. The endocannabinoid system regulates several functions of the adipose tissues to favor energy accumulation. In this review we will describe the presence of the endocannabinoid system in the adipose tissue. We will survey the role of the endocannabinoid system in the regulation of white and brown adipose tissue metabolism and how the eCB system participates in obesity and metabolic diseases.

Peripherally Selective CB1 Receptor Antagonist Improves Symptoms of Metabolic Syndrome in Mice

Metabolic syndrome (MetS) is a complex disorder that stems from the additive effects of multiple underlying causes such as obesity, insulin resistance, and chronic low-grade inflammation. The endocannabinoid system plays a central role in appetite regulation, energy balance, lipid metabolism, insulin sensitivity, and β-cell function. The type 1 cannabinoid receptor (CB1R) antagonist SR141716A (rimonabant) showed promising antiobesity effects, but its use was discontinued due to adverse psychiatric events in some users. These adverse effects are due to antagonism of CB1R in the central nervous system (CNS). As such, CNS-sparing CB1R antagonists are presently being developed for various indications. In this study, we report that a recently described compound, 3-{1-[8-(2-chlorophenyl)-9-(4-chlorophenyl)-9H-purin-6-yl]piperidin-4-yl}-1-[6-(difluoromethoxy)pyridin-3-yl]urea (RTI1092769), a pyrazole based weak inverse agonist/antagonist of CB1 with very limited brain exposure, improves MetS related complications. Treatment with RTI1092769 inhibited weight gain and improved glucose utilization in obese mice maintained on a high fat diet. Hepatic triglyceride content and steatosis significantly improved with treatment. These phenotypes were supported by improvement in several biomarkers associated with nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). These results reinforce the idea that CB1 antagonists with limited brain exposure should be pursued for MetS and other important indications.

Neurochemical regulators of food behavior for pharmacological treatment of obesity: current status and future prospects

In recent decades, obesity has become a pandemic disease and appears to be an ultimate medical and social problem. Existing antiobesity drugs show low efficiency and a wide variety of side effects. In this review, we discuss possible mechanisms underlying brain-gut-adipose tissue axis, as well as molecular biochemical characteristics of various neurochemical regulators of body weight and appetite. Multiple brain regions are responsible for eating behavior, hedonic eating and food addiction. The existing pharmacological targets for treatment of obesity were reviewed as well.

Behavioral assessment of rimonabant under acute and chronic conditions

Cannabinoid subtype 1 receptor (CB1R) antagonists were originally developed as anti-obesity agents. Unfortunately, SR1417116A (rimonabant), the first marketed inverse agonist of CB1R, produced CNS-related adverse effects including depression and suicidal ideation, and thus it was withdrawn from the market. These effects of rimonabant became evident in patients following chronic dosing. Standard preclinical toxicity studies failed to detect these adverse effects. The goal of these studies was to perform an integrated battery of behavioral assays to better understand the behavioral effects of rimonabant following both acute and chronic administration. In the present study, acute dosing with rimonabant in rats significantly decreased food consumption; decreased measures of locomotor activity; increased scratching, grooming and wet-dog shakes; and increased defecation. Subsequently, animals were tested using a chronic dosing regimen but prior to drug administration for that day. The highest dose of rimonabant tested significantly decreased marble burying behavior, presumably anxiolysis. There were also significant effects in social interaction after chronic dosing. Our results did not reveal significant rimonabant-induced anxiogenic behaviors. Future studies to characterize behavioral screens for anxiogenic effects of CB1 antagonists in rodents should further explore social interaction paradigms and potential comorbid factors of rimonabant dosing such as sex, age, and obesity.

Undergraduate and postgraduate pharmacovigilance education: A proposal for appropriate curriculum content

BACKGROUND

Adverse drug reactions (ADRs) are common, often preventable, and a leading cause of morbidity and mortality. Pharmacovigilance (PV) involves detection, assessment, understanding, and prevention of adverse effects or any other drug-related problem. Education of healthcare professionals (HCPs) involved in drug prescription, dispensing and administration is essential to help prevent and mitigate both ADRs and medication errors and has to be focused on 3 pivotal aspects: •Awareness: All medicines can produce adverse effects. ADRs should always be considered as part of the differential diagnosis if any new adverse condition, symptoms or signs appear after a drug administration or during or after pharmacological treatment. •Knowledge: HCPs must have a sound understanding of the most frequently prescribed drugs and over-the-counter medications, factors that make patients more likely to benefit or more susceptible to harm, as well as of causes of medication errors. •Reporting: HCPs should know how to report ADRs and the role of reporting on regulatory aspects and scientific knowledge. Undergraduate curricula must provide, at a minimum, sufficient skills that warrant the appropriate and safe prescription/dispensing/administration of medications in clinical practice, focusing both on therapeutic effects and prevention of harm. Clinical appraisal skills must include ADRs as differential diagnosis, taking accurate medication history, basic individual causality assessment, identification and proper management of ADRs, and informing patients of possible ADRs. Postgraduate periodic PV training should be mandatory as part of continuing education. Specialised postgraduate education should include advanced contents.

State of the Art Review: Long-term Pharmacotherapy for Overweight and Obesity: A Review of Sibutramine, Orlistat, and Rimonabant

The objective of this review is to evaluate the safety and efficacy of pharmacotherapy for long-term maintenance of weight loss in overweight and obese patients. Literature was obtained through a MEDLINE (1966 to July 2006) search and a bibliographic review of published articles. Key terms used included overweight, obesity, sibutramine, orlistat, and rimonabant. The search was further limited to clinical trials in humans and in the English language. Obesity is a chronic condition requiring long-term therapy. Two agents, sibutramine and orlistat, are currently approved by the Food and Drug Administration for the long-term treatment of obesity. Rimonabant, marketed in Europe as Accomplia, has demonstrated efficacy for long term weight loss, however an Food and Drug Administration advisory panel voted against its approval in June 2007 due to safety concerns (psychiatric effects). For clinically meaningful results, these agents must be used in conjunction with lifestyle therapy, including a hypocaloric diet, increased physical activity, and behavioral modification. This article reviews clinical trials evaluating the safety and efficacy of sibutramine, orlistat, and rimonabant in reducing weight and examines other health benefits and risks associated with these agents.

The role of gastrointestinal vagal afferent fibres in obesity

Gastrointestinal (GI) vagal afferents are a key mediatory of food intake. Through a balance of responses to chemical and mechanical stimuli food intake can be tightly controlled via the ascending satiety signals initiated in the GI tract. However, vagal responses to both mechanical and chemical stimuli are modified in diet-induced obesity (DIO). Much of the research to date whilst in relatively isolated/controlled circumstances indicates a shift between a balance of orexigenic and anorexigenic vagal signals to blunted anorexigenic and potentiated orexigenic capacity. Although the mechanism responsible for the DIO shift in GI vagal afferent signalling is unknown, one possible contributing factor is the gut microbiota. Nevertheless, whatever the mechanism, the observed changes in gastrointestinal vagal afferent signalling may underlie the pathophysiological changes in food consumption that are pivotal for the development and maintenance of obesity.

Pharmacotherapies for Overeating and Obesity

Obesity has become pandemic, and the annual cost in related illnesses and loss of productivity is already over $100 billion and rising. Research has shown that obesity can and does cause changes in behavior and in the brain itself that are very similar to changes caused by drugs of abuse. While food addiction is not the causal agent of all obesity, it is clear that many people no longer eat to survive, but instead survive to eat. This review considers the importance of the brain's reward system in food intake. The review also examines research developments and current treatments for obesity, including diet and exercise, psychotherapy, surgical interventions, and pharmacotherapies. Finally we discuss alterations in American society that are necessary for change to occur, and the diffculties therein.

Weight loss interventions for chronic asthma

BACKGROUND

Asthma and obesity are both public health problems with increasing prevalence globally. Several epidemiological studies have shown an association between asthma and obesity, however there is no good quality evidence on the effect of weight loss on asthma control.

OBJECTIVES

To assess the effect of various interventions for weight loss on measures of asthma control and weight loss amongst overweight or obese patients with chronic asthma.

SEARCH METHODS

We searched the Cochrane Airways Group's Specialized Register of Trials (CAGR) (derived from systematic searches of bibliographic databases, including the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, CINAHL, AMED and PsycINFO, and handsearching of respiratory journals and meeting abstracts). We also searched ongoing trials web sites and dissertation databases up to March 2012. We contacted experts in the field and searched reference lists for additional studies.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of weight loss interventions for overweight or obese participants with asthma compared to either no intervention for weight loss or an alternative weight loss intervention.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility and risk of bias, and extracted data using a data extraction form. We did not undertake any meta-analysis as there were no suitable data to combine.

MAIN RESULTS

We included four completed studies conducted amongst adults (n = 197). Two were published as abstracts, and two as full articles. Interventions included supervised physical activity, low calorie diet and anti-obesity drugs (singly or in combination), and were compared to usual care (two studies), low calorie diet (one study), while one study had three intervention arms (physical activity versus low calorie diet versus a combination of the two). Two studies were conducted in high-income countries, while two were conducted in upper, middle-income countries.All studies had an unclear risk of selection and a high risk of detection bias. One of the studies found a statistically significant reduction in symptoms scores in treatment compared to control groups: the difference between groups in total St. George's Respiratory Questionnaire (SGRQ) score was -10 units (95% CI -18 to-1; P = 0.02). One study showed reduction in doses of rescue medication in treatment compared with control groups in the short term. Weight loss was associated with some improvement in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) in one study, which was statistically significant, but clinically unimportant; there was no improvement in peak expiratory flow rate (PEFR). No data were reported on health care utilization and adverse effects. One study reported statistically significant weight loss in the treatment group compared to controls with no intervention, which was still significant at one year follow-up.

AUTHORS' CONCLUSIONS

Implications for practice This review found one randomized trial that showed that weight loss may be beneficial for improving asthma control in overweight and obese patients, in conjunction with weight loss in intervention groups in the short term. Applying the GRADE system to the results of this review however, shows that the quality of evidence is low, because although all four studies are RCTs there were serious methodological limitations in the studies (unclear risk of selection bias and high risk of detection bias) and imprecision (small sample size). There is inadequate evidence to comment on the effect of weight loss interventions on quality of life and health care utilization. In addition, there was inadequate reporting of data on adverse effects to permit proper balancing of harms and benefits of the interventions. On account of this low quality of evidence, the benefit of weight loss as an intervention for asthma control remains uncertain, and as such, clinicians should be prepared to help patients to make a decision that is consistent with their own values.Implications for research The finding that most of the included studies were of low methodological quality highlights the need for further well designed RCTs, with emphasis on adequate methods of allocation sequence generation as well as allocation concealment and longer follow-up periods. These studies need to report more fully on relevant outcomes (both statistically significant and otherwise) such as: asthma symptoms/control, use of rescue medication, change in lung function parameters (actual mean/median values), hospital utilization, quality of life, and adverse effects. There is also a need for longer intervention as well as follow-up durations to evaluate the effect of sustained measures to achieve weight loss, and to determine if these effects are still significantly present after a considerable period of time.There is also a need for these well designed studies in children and adolescents, as well as in low-income countries such as Africa, where the prepackaged, low energy diets, as well as structured physical activity-based interventions utilized in these included studies, may not be feasible or applicable.

Cannabinoid type 1 receptor antagonists for smoking cessation

BACKGROUND

Selective type 1 cannabinoid (CB1) receptor antagonists may assist with smoking cessation by restoring the balance of the endocannabinoid system, which can be disrupted by prolonged use of nicotine. They also seeks to address many smokers' reluctance to persist with a quit attempt because of concerns about weight gain.

OBJECTIVES

To determine whether selective CB1 receptor antagonists (currently rimonabant and taranabant) increase the numbers of people stopping smoking To assess their effects on weight change in successful quitters and in those who try to quit but fail.

SEARCH STRATEGY

We searched the Cochrane Tobacco Addiction Review Group specialized register for trials, using the terms ('rimonabant' or 'taranabant') and 'smoking' in the title or abstract, or as keywords. We also searched MEDLINE, EMBASE, CINAHL and PsycINFO, using major MESH terms. We acquired electronic or paper copies of posters of preliminary trial results presented at the American Thoracic Society Meeting in 2005, and at the Society for Research on Nicotine and Tobacco European Meeting 2006. We also attempted to contact the authors of ongoing studies of rimonabant, and Sanofi Aventis (manufacturers of rimonabant). The most recent search was in January 2011.

SELECTION CRITERIA

Types of studies Randomized controlled trialsTypes of participants Adult smokersTypes of interventions Selective CB1 receptor antagonists, such as rimonabant and taranabant. Types of outcome measures The primary outcome is smoking status at a minimum of six months after the start of treatment. We preferred sustained cessation rates to point prevalence, and biochemically verified cessation to self-reported quitting. We regarded smokers who drop out or are lost to follow up as continuing smokers. We have noted any adverse effects of treatment.A secondary outcome is weight change associated with the cessation attempt.

DATA COLLECTION AND ANALYSIS

Two authors checked the abstracts for relevance, and attempted to acquire full trial reports. One author extracted the data, and a second author checked them.

MAIN RESULTS

We found three trials which met our inclusion criteria, covering 1567 smokers (cessation: STRATUS-EU and STRATUS-US), and 1661 quitters (relapse prevention: STRATUS-WW). At one year, the pooled risk ratio (RR) for quitting with rimonabant 20 mg was 1.50 (95% confidence interval (CI) 1.10 to 2.05). No significant benefit was demonstrated for rimonabant at 5 mg dosage. Adverse events included nausea and upper respiratory tract infections. In the relapse prevention trial, smokers who had quit on the 20 mg regimen were more likely to remain abstinent on either active regimen than on placebo; the RR for the 20 mg maintenance group was 1.29 (95% CI 1.06 to 1.57), and for the 5 mg maintenance group 1.30 (95% CI 1.06 to 1.59). There appeared to be no significant benefit of maintenance treatment for the 5 mg quitters. One trial of taranabant was not included in our meta-analyses, as it followed participants only until end of treatment; at eight weeks it found no benefit for treatment over placebo, with an OR of 1.2 (90% CI 0.6 to 2.5). For rimonabant, weight gain was reported to be significantly lower among the 20 mg quitters than in the 5 mg or placebo quitters. During treatment, overweight or obese smokers tended to lose weight, while normal weight smokers did not. For taranabant, weight gain was significantly lower for 2-8 mg versus placebo at the end of eight weeks of treatment. In 2008, post-marketing surveillance led the European Medicines Agency (EMEA) to require Sanofi Aventis to withdraw rimonabant, because of links to mental disorders. The development of taranabant was also suspended by Merck & Co because of unacceptable adverse events.

AUTHORS' CONCLUSIONS

From the trial reports available, rimonabant 20 mg may increase the chances of quitting approximately 1½-fold. The evidence for rimonabant in maintaining abstinence is inconclusive. Rimonabant 20 mg may moderate weight gain in the long term. Taranabant 2-8 mg may moderate weight gain, at least in the short term. In 2008, development of both rimonabant and taranabant was discontinued by the manufacturers.

Rimonabant: From RIO to Ban

Endocannabinoid antagonism as a treatment for obesity and the metabolic syndrome became a hugely anticipated area of pharmacology at the start of the century. The CB1 receptor antagonist Rimonabant entered the European mass market on the back of several trials showing weight loss benefits alongside improvements in numerous other elements of the metabolic syndrome. However, the drug was quickly withdrawn due to the emergence of significant side effects-notably severe mood disorders. This paper provides a brief overview of the Rimonabant story and places the recent spate of FDA rejections of other centrally acting weight loss drugs entering Phase 3 trials in this context.

Pharmacotherapies for obesity: past, current, and future therapies

Past therapies for the treatment of obesity have typically involved pharmacological agents usually in combination with a calorie-controlled diet. This paper reviews the efficacy and safety of pharmacotherapies for obesity focusing on drugs approved for long-term therapy (orlistat), drugs approved for short-term use (amfepramone [diethylpropion], phentermine), recently withdrawn therapies (rimonabant, sibutamine) and drugs evaluated in Phase III studies (taranabant, pramlintide, lorcaserin and tesofensine and combination therapies of topiramate plus phentermine, bupropion plus naltrexone, and bupropion plus zonisamide). No current pharmacotherapy possesses the efficacy needed to produce substantial weight loss in morbidly obese patients. Meta-analyses support a significant though modest loss in bodyweight with a mean weight difference of 4.7 kg (95% CI 4.1 to 5.3 kg) for rimonabant, 4.2 kg (95% CI 3.6 to 4.8 kg) for sibutramine and 2.9 kg (95% CI 2.5 to 3.2 kg) for orlistat compared to placebo at ≥12 months. Of the Phase III pharmacotherapies, lorcaserin, taranabant, topiramate and bupropion with naltrexone have demonstrated significant weight loss compared to placebo at ≥12 months. Some pharmacotherapies have also demonstrated clinical benefits. Further studies are required in some populations such as younger and older people whilst the long term safety continues to be a major consideration and has led to the withdrawal of several drugs.

The novel cannabinoid CB1 antagonist AM6545 suppresses food intake and food-reinforced behavior

Drugs that interfere with cannabinoid CB1 transmission suppress food-motivated behaviors, and may be useful clinically as appetite suppressants. However, there may also be undesirable side effects (e.g., nausea, malaise, anxiety, and depression) that are produced by the current generation of CB1 inverse agonists such as rimonabant and taranabant. For that reason, it is important to continue research on novel cannabinoid antagonists. The present studies examined the effects of the novel compound AM6545, which is a neutral antagonist of CB1 receptors that is thought to have relatively poor penetrability into the central nervous system. Intraperitoneal administration of AM6545 significantly reduced food-reinforced operant responding at doses of 4.0, 8.0 and 16.0 mg/kg. AM6545 also produced a strong suppression of the intake of high-carbohydrate and high-fat diets in the same dose range, but only produced a mild suppression of lab chow intake at the highest dose (16.0 mg/kg). Although AM6545 did not affect food handling, it did reduce time spent feeding and feeding rate. Taken together, these results suggest that AM6545 is a compound that warrants further study as a potential appetite suppressant drug.

Tackling obesity: new therapeutic agents for assisted weight loss

The pandemic of overweight and obesity continues to rise in an alarming rate in western countries and around the globe representing a major public health challenge in desperate need for new strategies tackling obesity. In the United States nearly two thirds of the population is overweight or obese. Worldwide the number of persons who are overweight or obese exceeded 1.6 billion. These rising figures have been clearly associated with increased morbidity and mortality. For example, in the Framingham study, the risk of death increases with each additional pound of weight gain even in the relatively younger population between 30 and 42 years of age. Overweight and obesity are also associated with increased co-morbid conditions such as diabetes, hypertension and cardiovascular disease as well as certain types of cancer. In this review we discuss the epidemic of obesity, highlighting the pathophysiologic mechanisms of weight gain. We also provide an overview of the assessment of overweight and obese individuals discussing possible secondary causes of obesity. In a detailed section we discuss the currently approved therapeutic interventions for obesity highlighting their mechanisms of action and evidence of their efficacy and safety as provided in clinical trials. Finally, we discuss novel therapeutic interventions that are in various stages of development with a special section on the weight loss effects of anti-diabetic medications. These agents are particularly attractive options for our growing population of obese diabetic individuals.

The CB1 inverse agonist AM251, but not the CB1 antagonist AM4113, enhances retention of contextual fear conditioning in rats

The effects of CB1 antagonist/inverse agonists on the acquisition and consolidation of conditioned fear remain uncertain. Recent studies suggest that the CB1 antagonist/inverse agonist AM251 affects acquisition or consolidation of both contextual and discretely cued fear memories. AM251 is frequently referred to as a CB1 antagonist; however in vitro signal transduction assays indicate that this drug also elicits inverse agonist activity at CB1 receptors. The present studies were undertaken to compare the effects of AM251 on conditioned fear with those produced by AM4113, a novel CB1 antagonist with minimal inverse agonist activity. All drugs were administered prior to conditioning. In retention tests conducted two weeks after conditioning, both AM251 (4.0 mg/kg) and AM4113 (6.0 mg/kg)-treated animals exhibited reduced freezing during a conditioned tone cue played within a novel context. In contextual fear retention tests, animals previously treated with 4.0 or 8.0 mg/kg AM251 exhibited enhanced freezing. By contrast, no dose of AM4113 had any significant effect on contextual fear memory, which is consistent with the lower signal transduction activity of AM4113 at CB1 receptors compared to AM251. These results suggest that CB1 neutral antagonists may be less likely than CB1 inverse agonists to facilitate the acquisition or consolidation of contextual fear that may contribute to some clinical disorders.

Interventions to change the behaviour of health professionals and the organisation of care to promote weight reduction in overweight and obese people

BACKGROUND

The prevalence of obesity is increasing globally and will, if left unchecked, have major implications for both population health and costs to health services.

OBJECTIVES

To assess the effectiveness of strategies to change the behaviour of health professionals and the organisation of care to promote weight reduction in overweight and obese people.

SEARCH STRATEGY

We updated the search for primary studies in the following databases, which were all interrogated from the previous (version 2) search date to May 2009: The Cochrane Central Register of Controlled Trials (which at this time incorporated all EPOC Specialised Register material) (The Cochrane Library 2009, Issue 1), MEDLINE (Ovid), EMBASE (Ovid), CINAHL (EBSCO), and PsycINFO (Ovid). We identified further potentially relevant studies from the reference lists of included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared routine provision of care with interventions aimed either at changing the behaviour of healthcare professionals or the organisation of care to promote weight reduction in overweight or obese adults.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

We included six RCTs, involving more than 246 health professionals and 1324 overweight or obese patients. Four of the trials targeted professionals and two targeted the organisation of care. Most of the studies had methodological or reporting weaknesses indicating a risk of bias.Meta-analysis of three trials that evaluated educational interventions aimed at GPs suggested that, compared to standard care, such interventions could reduce the average weight of patients after a year (by 1.2 kg, 95% CI -0.4 to 2.8 kg); however, there was moderate unexplained heterogeneity between their results (I(2) = 41%). One trial found that reminders could change doctors' practice, resulting in a significant reduction in weight among men (by 11.2 kg, 95% CI 1.7 to 20.7 kg) but not among women (who reduced weight by 1.3 kg, 95% CI -4.1 to 6.7 kg). One trial found that patients may lose more weight after a year if the care was provided by a dietitian (by 5.6 kg, 95% CI 4.8 to 6.4 kg) or by a doctor-dietitian team (by 6 kg, 95% CI 5 to 7 kg), as compared with standard care. One trial found no significant difference between standard care and either mail or phone interventions in reducing patients' weight.

AUTHORS' CONCLUSIONS

Most of the included trials had methodological or reporting weaknesses and were heterogeneous in terms of participants, interventions, outcomes, and settings, so we cannot draw any firm conclusions about the effectiveness of the interventions. All of the evaluated interventions would need further investigation before it was possible to recommend them as effective strategies.

Obesity and preclinical changes of cardiac geometry and function

Overweight and obesity are rapidly increasing in prevalence due to adoption of the westernized life style in Korea. Obesity is strongly associated with the development of cardiovascular risk factors such as diabetes, hypertension, and dyslipidemia. In addition, accumulating evidence suggests that obesity per se has a direct effect on cardiac functional and structural changes that may not be the result of atherosclerosis. In this review, we focus on the view that obesity can influence on the structural and functional changes of the heart, drawing evidence from human and animal studies. We also review influencing factors such as physical, neurohormonal, and metabolic alterations that are associated with changes of the heart in obesity.

Potential anxiogenic effects of cannabinoid CB1 receptor antagonists/inverse agonists in rats: comparisons between AM4113, AM251, and the benzodiazepine inverse agonist FG-7142

Cannabinoid CB1 inverse agonists suppress food-motivated behaviors, but may also induce psychiatric effects such as depression and anxiety. To evaluate behaviors potentially related to anxiety, the present experiments assessed the CB1 inverse agonist AM251 (2.0-8.0mg/kg), the CB1 antagonist AM4113 (3.0-12.0mg/kg), and the benzodiazepine inverse agonist FG-7142 (10.0-20.0mg/kg), using the open field test and the elevated plus maze. Although all three drugs affected open field behavior, these effects were largely due to actions on locomotion. In the elevated plus maze, FG-7142 and AM251 both produced anxiogenic effects. FG-7142 and AM251 also significantly increased c-Fos activity in the amygdala and nucleus accumbens shell. In contrast, AM4113 failed to affect performance in the plus maze, and did not induce c-Fos immunoreactivity. The weak effects of AM4113 are consistent with biochemical data showing that AM4113 induces little or no intrinsic cellular activity. This research may lead to the development of novel appetite suppressants with reduced anxiogenic effects.

Cannabinoids for clinicians: the rise and fall of the cannabinoid antagonists

The endocannabinoid system has emerged as a significant player in the control of energy balance and metabolism, through its direct central and peripheral effects, as well as via its interaction with other appetite-regulating pathways. There is mounting evidence that the endocannabinoid system is overactive in obesity and were it possible to safely dampen-down the elevated endocannabinoid tone, lipid and carbohydrate profiles could be improved and weight loss induced. The series of randomised clinical trials showed reproducible beneficial effects on weight, HbA1c and lipid parameters, in addition to other cardiovascular risk factors. However, to date, clinical developments have been halted because of psychiatric side effects. Although recent evidence has highlighted the importance of an appetite-independent, peripheral mode of action, it is still unclear whether selectively blocking the peripheral system could potentially solve the problem of the central side effects, which thus far has led to the demise of the cannabinoid antagonists as useful pharmaceuticals. In this concise review, we summarise the data on the metabolic effects of the cannabinoid pathway and its antagonists.

Systematic review and meta-analysis on the adverse events of rimonabant treatment: considerations for its potential use in hepatology

Background

The cannabinoid-1 receptor blockers have been proposed in the management of obesity and obesity-related liver diseases (fatty liver as NAFLD or NASH). Due to increasing number of patients to be potentially treated and the need to assess the advantage of this treatment in terms of risk/benefit, we analyze the side events reported during the treatment with rimonabant by a systematic review and meta-analysis of all randomized controlled studies.

Methods

All published randomized controlled trials using rimonabant versus placebo in adult subjects were retrieved. Relative risks (RR) with 95% confidence interval for relevant adverse events and number needed to harm was calculated.

Results

Nine trials (n = 9635) were considered. Rimonabant 20 mg was associated with an increased risk of adverse event (RR 1.35; 95%CI 1.17-1.56), increased discontinuation rate (RR 1.79; 95%CI 1.35-2.38), psychiatric (RR 2.35; 95%CI 1.66-3.34), and nervous system adverse events (RR 2.35; 95%CI 1.49-3.70). The number needed to harm for psychiatric adverse events is 30.

Conclusion

Rimonabant is associated with an increased risk of adverse events. Despite of an increasing interest for its use on fatty liver, the security profile and efficacy it is needs to be carefully assessed before its recommendation. At present the use of rimonabant on fatty liver cannot be recommended.

Intracerebroventricular administration of cannabinoid CB1 receptor antagonists AM251 and AM4113 fails to alter food-reinforced behavior in rats

RATIONALE

Drugs that interfere with cannabinoid CB1 transmission suppress food-motivated behaviors and may be useful as appetite suppressants, but there is uncertainty about the locus of action for the feeding-suppression effects of these drugs.

OBJECTIVE

The present work was conducted to determine if two drugs that interfere with cannabinoid receptor transmission, AM251 and AM4113, have effects on food-reinforced behavior after administration into the lateral ventricle (intracerebroventricular (ICV)).

RESULTS

Although systemic administration of both drugs can suppress food-reinforced behavior, neither AM251 (40, 80, and 160 microg) nor AM4113 (60, 120, and 240 microg) administered at various times prior to testing produced any suppression of food-reinforced operant responding on a fixed-ratio 5 schedule. Because the modulation of locomotion by drugs that act on CB1 receptors is hypothesized to be a forebrain effect, these drugs also were assessed for their ability to reverse the locomotor suppression produced by the CB1 agonist AM411. ICV administration of either AM251 or AM4113 reversed the locomotor suppression induced by the CB1 agonist AM411 in the same dose range that failed to produce any effects on feeding.

CONCLUSIONS

This indicates that both AM4113 and AM251, when administered ICV, can interact with forebrain CB1 receptors and are efficacious on forebrain-mediated functions unrelated to feeding. These results suggest that CB1 neutral antagonists or inverse agonists may not be affecting food-reinforced behavior via interactions with forebrain CB1 receptors located in nucleus accumbens or hypothalamus and that lower brainstem or peripheral receptors may be involved.

Appetite suppressants, cardiac valve disease and combination pharmacotherapy

The prevalence of obesity in the United States is a major health problem associated with significant morbidity, mortality, and economic burden. Although obesity and drug addiction are typically considered distinct clinical entities, both diseases involve dysregulation of biogenic amine neuron systems in the brain. Thus, research efforts to develop medications for treating drug addiction can contribute insights into the pharmacotherapy for obesity. Here, we review the neurochemical mechanisms of selected stimulant medications used in the treatment of obesity and issues related to fenfluramine-associated cardiac valvulopathy. In particular, we discuss the evidence that cardiac valve disease involves activation of mitogenic serotonin 2B (5-HT2B) receptors by norfenfluramine, the major metabolite of fenfluramine. Advances in medication discovery suggest that novel molecular entities that target 2 different neurochemical mechanisms, that is, "combination pharmacotherapy," will yield efficacious antiobesity medications with reduced adverse side effects.

Sample size in obesity trials: patient perspective versus current practice

OBJECTIVE

To evaluate patient opinions on acceptable risks in exchange for a given degree of weight loss and their implications for sample size determination in obesity randomized clinical trials (RCTs).

DESIGN

. Survey of patients entering RCTs for weight loss in a university-based clinical research setting and power calculations based on their responses. Participants. Men (n = 8) and women (n = 66) between 24 and 73 years of age with body mass indices ranging from 26.8 to 40.5 kg/m(2). Measurements. Survey responses to questions assessing the added risk of serious adverse events (SAEs) or death one is willing to assume for a given degree of weight loss.

RESULTS

For 5% and 10% weight loss against risk for death per se, the mean acceptable risk tended to be about 3.5%, but the median (0.00) and mode (0.00) suggested that for most individuals, only a risk of < or = 1% would be acceptable. Figures, estimated dropout rates, and base rates of SAEs (including deaths) from recent obesity trials indicate that 1-year 2-group obesity RCTs would need tens of thousands of participants per group to have 80% power to detect risks that are meaningful to patients at the 2-tailed 0.05 alpha level.

CONCLUSION

Patient education is needed to explain which risks are realistically detectable in RCTs so that patients may provide truly informed consent, or RCT standards should be modified to meet patients' implicit expectations.

The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration

Systematic reviews and meta-analyses are essential to summarize evidence relating to efficacy and safety of health care interventions accurately and reliably. The clarity and transparency of these reports, however, is not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users.Since the development of the QUOROM (QUality Of Reporting Of Meta-analysis) Statement--a reporting guideline published in 1999--there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realizing these issues, an international group that included experienced authors and methodologists developed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions.The PRISMA Statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this Explanation and Elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA Statement, this document, and the associated Web site (http://www.prisma-statement.org/) should be helpful resources to improve reporting of systematic reviews and meta-analyses.

The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration

Systematic reviews and meta-analyses are essential to summarize evidence relating to efficacy and safety of health care interventions accurately and reliably. The clarity and transparency of these reports, however, is not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users.Since the development of the QUOROM (QUality Of Reporting Of Meta-analysis) Statement--a reporting guideline published in 1999--there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realizing these issues, an international group that included experienced authors and methodologists developed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions.The PRISMA Statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this Explanation and Elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA Statement, this document, and the associated Web site (http://www.prisma-statement.org/) should be helpful resources to improve reporting of systematic reviews and meta-analyses.

The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate healthcare interventions: explanation and elaboration

Systematic reviews and meta-analyses are essential to summarise evidence relating to efficacy and safety of healthcare interventions accurately and reliably. The clarity and transparency of these reports, however, are not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users. Since the development of the QUOROM (quality of reporting of meta-analysis) statement-a reporting guideline published in 1999-there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realising these issues, an international group that included experienced authors and methodologists developed PRISMA (preferred reporting items for systematic reviews and meta-analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions. The PRISMA statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this explanation and elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA statement, this document, and the associated website (www.prisma-statement.org/) should be helpful resources to improve reporting of systematic reviews and meta-analyses.

Gut hormones: implications for the treatment of obesity

Bariatric surgery is the only effective treatment for patients with morbid obesity. This is no solution to the present obesity pandemic however. Currently licensed non-surgical pharmaceuticals are of limited efficacy and alternatives are needed. Harnessing the body's own appetite-regulating signals is a desirable pharmacological strategy. The gastrointestinal tract has a prime role in sensing and signalling food intake to the brain. Gut hormones are key mediators of this information, including: peptide YY (PYY), pancreatic polypeptide (PP), glucagon-like peptide 1 (GLP-1), oxyntomodulin (OXM), ghrelin, amylin and cholecystokinin (CCK). This review summarises the latest knowledge regarding the physiological and pathophysiological role of gut hormones in regulating our food intake and how this knowledge could guide, or has guided, the development of weight-loss drugs. Up-to-date outcomes of clinical trials are evaluated and directions for the future suggested.

Lifestyle-induced metabolic inflexibility and accelerated ageing syndrome: insulin resistance, friend or foe?

The metabolic syndrome may have its origins in thriftiness, insulin resistance and one of the most ancient of all signalling systems, redox. Thriftiness results from an evolutionarily-driven propensity to minimise energy expenditure. This has to be balanced with the need to resist the oxidative stress from cellular signalling and pathogen resistance, giving rise to something we call 'redox-thriftiness'. This is based on the notion that mitochondria may be able to both amplify membrane-derived redox growth signals as well as negatively regulate them, resulting in an increased ATP/ROS ratio. We suggest that 'redox-thriftiness' leads to insulin resistance, which has the effect of both protecting the individual cell from excessive growth/inflammatory stress, while ensuring energy is channelled to the brain, the immune system, and for storage. We also suggest that fine tuning of redox-thriftiness is achieved by hormetic (mild stress) signals that stimulate mitochondrial biogenesis and resistance to oxidative stress, which improves metabolic flexibility. However, in a non-hormetic environment with excessive calories, the protective nature of this system may lead to escalating insulin resistance and rising oxidative stress due to metabolic inflexibility and mitochondrial overload. Thus, the mitochondrially-associated resistance to oxidative stress (and metabolic flexibility) may determine insulin resistance. Genetically and environmentally determined mitochondrial function may define a 'tipping point' where protective insulin resistance tips over to inflammatory insulin resistance. Many hormetic factors may induce mild mitochondrial stress and biogenesis, including exercise, fasting, temperature extremes, unsaturated fats, polyphenols, alcohol, and even metformin and statins. Without hormesis, a proposed redox-thriftiness tipping point might lead to a feed forward insulin resistance cycle in the presence of excess calories. We therefore suggest that as oxidative stress determines functional longevity, a rather more descriptive term for the metabolic syndrome is the 'lifestyle-induced metabolic inflexibility and accelerated ageing syndrome'. Ultimately, thriftiness is good for us as long as we have hormetic stimuli; unfortunately, mankind is attempting to remove all hormetic (stressful) stimuli from his environment.

Obesity, the endocannabinoid system, and bias arising from pharmaceutical sponsorship

BACKGROUND

Previous research has shown that academic physicians conflicted by funding from the pharmaceutical industry have corrupted evidence based medicine and helped enlarge the market for drugs. Physicians made pharmaceutical-friendly statements, engaged in disease mongering, and signed biased review articles ghost-authored by corporate employees. This paper tested the hypothesis that bias affects review articles regarding rimonabant, an anti-obesity drug that blocks the central cannabinoid receptor.

METHODS/PRINCIPAL FINDINGS

A MEDLINE search was performed for rimonabant review articles, limited to articles authored by USA physicians who served as consultants for the company that manufactures rimonabant. Extracted articles were examined for industry-friendly bias, identified by three methods: analysis with a validated instrument for monitoring bias in continuing medical education (CME); analysis for bias defined as statements that ran contrary to external evidence; and a tally of misrepresentations about the endocannabinoid system. Eight review articles were identified, but only three disclosed authors' financial conflicts of interest, despite easily accessible information to the contrary. The Takhar CME bias instrument demonstrated statistically significant bias in all the review articles. Biased statements that were nearly identical reappeared in the articles, including disease mongering, exaggerating rimonabant's efficacy and safety, lack of criticisms regarding rimonabant clinical trials, and speculations about surrogate markers stated as facts. Distinctive and identical misrepresentations regarding the endocannabinoid system also reappeared in articles by different authors.

CONCLUSIONS

The findings are characteristic of bias that arises from financial conflicts of interest, and suggestive of ghostwriting by a common author. Resolutions for this scenario are proposed.

Current pharmacotherapeutic concepts for the treatment of obesity in adults

Obesity is one of the greatest public health challenges of the twenty-first century. The World Health Organization (WHO) reports that in 2005 approximately 1.6 billion adults were overweight and at least 400 million adults were obese. The prevalence of obesity is still continuing to increase dramatically. Overweight and obese people carry a higher risk for a variety of cardiovascular diseases including hypertension, coronary heart disease, stroke and peripheral occlusive artery disease. Weight loss is considered to be the initial step which helps to prevent or to control the clinical consequences of obesity. In a great number of patients who are not able to reduce weight by means of non-pharmacological measures, drug therapy can assist in reaching the weight management targets. Drug treatment should only be considered as part of a systematic weight management program including dietary and lifestyle changes. This review summarizes current pharmacotherapeutic concepts for the treatment of obesity in adults focusing on efficacy and safety of anti-obesity drugs.

Neuropharmacology of human appetite expression

The regulation of appetite relies on the integration of numerous episodic (meal) and tonic (energy storage) generated signals in energy regulatory centres within the central nervous system (CNS). These centers provide the pharmacological potential to modify human appetite (hunger and satiety) to increase or decrease caloric intake, or to normalize aberrant eating behavior. With regard to obesity, the satiety enhancing anti-obesity drug sibutramine has proved effective at reducing body weight. Additionally, the endocannabinoid CB(1) antagonist rimonabant has recently been approved for use in Europe (but not in the US). A 5-HT(2C) agonist lorcaserin is also currently undergoing large-scale clinical trials, but the effect of the drug on human appetite is unknown as yet. Appetite enhancing drugs such as magestrol acetate and dronabiol are currently used to promote weight gain. Finally, sibutramine, selective serotonergic reuptake inhibitors such as fluoxetine and some anti-epileptic drugs have all been used to normalise aberrant eating behaviour. All these drugs act by modifying the expression of human appetite. An assessment of a drug's effects on caloric intake and feelings of hunger and satiety is necessary before they can be considered for clinical use.

A comparison between rimonabant and metformin in reducing biochemical hyperandrogenaemia and insulin resistance in patients with polycystic ovary syndrome (PCOS): a randomized open-label parallel study

CONTEXT

Weight loss and metformin therapy are reported to be beneficial in improving the biochemical hyperandrogenaemia and insulin resistance of polycystic ovary syndrome (PCOS). Rimonabant has been found to reduce weight and improve the metabolic profile in patients with obesity, type 2 diabetes and metabolic syndrome.

OBJECTIVE

To compare the effects of insulin sensitization with metformin to weight reduction by rimonabant on biochemical hyperandrogenaemia and insulin resistance in patients with PCOS.

DESIGN

A randomized, open-label parallel study.

SETTING

Endocrinology outpatient clinic in a referral centre.

SUBJECTS

Twenty patients with PCOS and biochemical hyperandrogenaemia with a body mass index (BMI) >or= 30 kg/m(2) were recruited.

INTERVENTION

Patients were randomized to 1.5 g daily of metformin or 20 mg daily of rimonabant.

MAIN OUTCOME MEASURES

The primary end-point of the study was a change in total testosterone.

RESULTS

After 12 weeks of rimonabant there was a significant reduction (mean +/- SEM) in weight (104.6 +/- 4.6 vs. 98.4 +/- 4.7 kg, P < 0.01), waist circumference (116.0 +/- 3.3 vs. 109.2 +/- 3.7 cm, P < 0.01), hip circumference (128.5 +/- 4.0 vs. 124.1 +/- 4.2 cm, P < 0.03), waist-hip ratio (0.90 +/- 0.02 vs. 0.88 +/- 0.01, P < 0.01) free androgen index (FAI) (26.6 +/- 6.1 vs. 16.6 +/- 4.1, P < 0.01), testosterone [4.6 +/- 0.4 vs. 3.1 +/- 0.3 nmol/l (132.7 +/- 11.5 vs. 89.4 +/- 8.65 ng/dl), P < 0.01] and insulin resistance as measured by the homeostasis model assessment (HOMA) method (4.4 +/- 0.5 vs. 3.4 +/- 0.4, P = 0.05). There was no change in any of these parameters in the metformin-treated group.

CONCLUSION

This study suggests that the weight loss through rimonabant therapy may be of use in patients with PCOS and appears superior to insulin sensitization by metformin in reducing the FAI and insulin resistance in obese PCOS patients treated over a 12-week period.

Cost-effectiveness of pharmacological anti-obesity treatments: a systematic review

AIM

To review economic evaluations of weight loss drugs and compare reported incremental cost-effectiveness ratios (ICERs).

METHODS

A literature search was conducted for cost-effectiveness (CEAs) and cost-utility analyses (CUAs) of sibutramine, orlistat and rimonabant.

RESULTS

Fourteen unique articles were identified (11 CUAs and 3 CEAs; 9 orlistat, 4 sibutramine and 1 rimonabant). All used diet and exercise as comparator, whereas none included indirect costs. Time horizons varied from treatment period only (1-4 years) to 80 years (median 7.5 years). Longer studies modeled effects on diabetes, micro- and macrovascular complications, coronary heart disease and death. Of the CUAs, the median ICER was 16,000 euro(2007)/QALY (quality-adjusted life-year; range 10,000-88,000), with the worst cost-effectiveness when recommended stop rules for non-responding patients were not applied. All studies but three were funded by the manufacturing company, and the median ICER was considerably higher for independent than for sponsored analyses (62,000 euro vs 15,000 euro/QALY). However, two of the three independent CUAs did not use recommended stop rules, as compared with one of eight manufacturer-sponsored analyses. The results were most sensitive to assumptions regarding weight loss sustainability and utility per kilogram lost. Side effects and dropout because of reasons other than lack of efficacy were generally not incorporated.

CONCLUSION

Published economic evaluations indicate that orlistat, sibutramine and rimonabant are within the range of what is generally regarded as cost-effective. Uncertainty remains about weight loss sustainability, utility gain associated with weight loss and extrapolations from transient weight loss to long-term health benefits. Modeling of head-to-head comparisons and attrition is needed, as are analyses conducted independently of manufacturing companies.

Long-term weight loss and weight-loss maintenance strategies

It has been suggested that about 20% of subjects undergoing weight-loss programmes can achieve a certain degree of long-term success. At present, surgery remains the only method resulting in long-term sustained weight loss, but access remains restricted. Hence it is important to analyse, in addition to pharmacotherapy, the methods to improve the effects of diet, exercise and behavioural modification. Since these techniques are less spectacular than others, there is a risk that their potential will be overlooked, in spite of the fact that they remain the main alternative for most subjects undergoing weight-loss therapy. This review summarizes realistic treatment alternatives and also provides data from a day care treatment, a strategy not much reported in the literature. This is a standard treatment modality for diabetes but less common in obesity treatment.

Disability pension, employment and obesity status: a systematic review

Disability pensions incur huge societal costs in many countries. In Sweden, the three greatest drivers of such productivity losses are musculo-skeletal, circulatory and psychiatric disorders, all closely associated with weight status. We identified 16 studies investigating the body mass index (BMI)-disability pension relation. In cross-sectional studies, a significantly greater proportion of obese compared with normal weight subjects were disability pensioners. In longitudinal studies, a J-shaped relation with BMI was generally found in both men and women of various ages. Different definitions of obesity status complicated interpretation, as several studies mixed the underweight and normal weight, which appear to have different disability pension risks. In middle-aged men, relative risks were elevated for circulatory causes only for the overweight and obese, while associations for mental disorders were similar in the underweight and overweight but much higher in the obese. In both sexes, monotonic increases and decreases were seen for circulatory and respiratory causes respectively. In intervention studies, reduced disability pension incidence and increased gainful employment were reported after surgery. In summary, BMI was significantly associated with disability pension, but the direction of causality may vary with underlying cause. Interventions had positive productivity effects in the morbidly obese, but whether this holds for the overweight remains to be proven.